cevnswith liquid argon scintillation detector(s)

1R. Tayloe, APS DPF 1908/19

CEvNS with liquid argon scintillation detector(s)R. Tayloe, Indiana U.for the COHERENT collaboration

Outline:• COHERENT at SNS• CEvNS with LAr• status/future of LAr detectors

for CEvNS

SNS “n-alley”

Vf2

2R. Tayloe, APS DPF 19

COHERENT experiment in SNS n-alley

08/19

SNS “n-alley”

• Low-background area • near (20-28 m) SNS target with• 1.4MW, 5000MWhr/yr, 1.5E23POT/yr, • pulsed beam (FWHM350 ns) at 60Hz

SNS n energy spectrum

Prompt nm from pdecay in time with the proton pulse

Delayed anti-nm, ne

on m decay timescale

SNS n time distribution


COHERENT experiment

08/19

recentlyremoved

First detection of CEvNS with CsI!

without/withnuclear FF


COHERENT experiment

08/19

recentlyremoved

• Next goal, demonstrate N2

dependence of CEvNS

• with CENNS-10 (liquid argon, LAr), currently running…


LAr for CEvNS

08/19

Liquid argon (LAr) is:

• Complementary to heavier Cs and I• Map out low N σ(CEvNS)• Lower σ but more energetic recoils

• Large scintillation yield• 40 photons/keVee

• Quenching factor well-measured

• Pulse Shape Discrimination (PSD) for particle ID!• Argon scintillates with 2 time constants

1. Singlet light: ~6 ns2. Triplet light: ~1.6 µs

• Electronic Recoils mostly triplet light• Nuclear Recoils mostly singlet light

event rates/kg/SNS-yr for COHERENT


LAr for CEvNS

08/19

Liquid argon (LAr) is:

• Complementary to heavier Cs and I• Map out low N σ(CEvNS)• Lower σ but more energetic recoils

• Large scintillation yield• 40 photons/keVee

• Quenching factor well-measured

• Pulse Shape Discrimination (PSD) for particle ID!• Argon scintillates with 2 time constants

1. Singlet light: ~6 ns2. Triplet light: ~1.6 µs

• Electronic Recoils mostly triplet light• Nuclear Recoils mostly singlet light

from ArDM

CENNS-10 detector currently running at SNS

timeline:• 2012-15: built at Fermilab (J. Yoo etal) for CENNS@Fermilab

effort, commissioned/upgraded at Indiana U.

• late 2016: moved to SNS, installed, shielding built

• early 2017: run with TPB-acrylic parts, Ethresh~80keVnr“Engineering Run”: 1.8GWhr collected, CEvNS rate low, constrain beam-related bckgrds, analysis finished

• mid-17: upgrade: TPB-Teflon reflectors, new TPB-coated PMTs, added 4” Pb shielding

• mid-17-present: run in upgraded mode, Ethresh~20keVnr“Production Run” : 6.1 GWhr collected,blind, 2 parallel, analyses in progressin US and Moscow


COHERENT LAr: CENNS-10

08/19

SNS “n-alley”

Liquefier

CENNS-10 with full shielding

Pumping cart

Gas rack

Cryocompressor

SC rack

DAQ rack

The CENNS-10 (LAr) Detector:

Specs:• 22 kg single-phase LAr fiducial volume• 2×8”PMTs TPB-coated, w/QE=18%@400 nm• TPB-coated PMTs/teflon side walls• Energy threshold ≈ 20keVnr• CAEN 1720 (250MHz, 12-bit) digitizer• 90W single-stage pulse-tube cold head• SAES MonoTorr gas purifier for ~1 ppm purity• Pb/Cu/H2O shield• Expect ≈140 CEvNS events/SNS-year • Running in current configuration since July ‘17

08/19 R. Tayloe, APS DPF 19 8

CENNS-10 Analysis for CEvNS:

Analysis Overview:

• Calibrate! , Calibrate!, Calibrate! with variety ofsources

• Characterize expected backgrounds in rate/time/energy

• Steady-state bkg from beam-off triggers• Beam-related neutrons with other neutron

detectors and CENNS-10 no-water runs

• Optimize energy/PID/time cuts on signal/noise

• Verify bkg subtraction with ‘pre-beam’ data

• “Open the Box”:1. Counting exp’t: prompt and delayed2. Full likelihood analysis


Prompt nm from p decay

Delayed anti-nm,

ne from m decay

SNS neutrino time distribution

Eng. run:steady-state bckgnd rate

vs energy

CENNS-10 Analysis for CEvNS:


Analysis Overview:

• Calibrate! , Calibrate!, Calibrate! with variety ofsources

• Characterize expected backgrounds in rate/time/energy

• Steady-state bkg from beam-off triggers• Beam-related neutrons with other neutron

detectors and CENNS-10 no-water runs

• Optimize energy/PID/time cuts on signal/noise

• Verify bkg subtraction with ‘pre-beam’ data

• “Open the Box”:1. Counting exp’t: prompt and delayed2. Full likelihood analysis

CENNS-10 no-water data

CENNS-10 Engineering run results:


blind analysis CENNS-10 Engineering run results:

• event excess in time with beam is consistent with expected prompt beam-related neutron rate

beam excess vs time

prompt beam excess vs energy




• event excess in time with beam is consistent with expected prompt beam-related neutron rate

• no event excess observed in delayed window with 0.5 events expected

• limit on delayed neutron backgrounds• limit on CEvNS cross section

beam excess vs time

prompt beam excess vs energy

delayed beam excess vs energy




• from full likelihood analysis: • cross section limits• non-standard interaction constraints

Eng. run CEvNS cross section limits

corresponding NSI regions

work ofIU PhD Student:Matthew Heath

\cite{Heath:2019jpj}

Production runs, 7/17-now: • light yield improved to ~4.5 PE/keV

• Particle ID (PSD), energy resolution/threshold sufficient for observation of CEvNS in 40Ar

• SM prediction ~130 CEvNS events inthis data set

• analyses in end stages, results soon!

R. Tayloe, APS DPF 1908/19

14

83mKr41 keVg source

Particle ID, AmBe source

CENNS-10 Production run:

Indiana U, Phd Student:Jacob Zettlemoyer

ITEP/MEPHI (Moscow), Phd Students: Dmitry Rudik, Alex Kumpan,

nuc. recoil

e/ recoil

Light yield vs energy


COHERENT future, next steps

08/19

Physics reach of CEvNS:

• Understanding supernovae (SN): • Expected to be important in

core-collapse SN and • possible SN detection channel.

• Nuclear Physics: nuclear form factors

• Standard Model tests, eg: NSI, sin2 qw , neutrino magnetic moments

• n oscillations: Investigation of nsterile

oscillations

• reactor monitoring (non-proliferation)

• Dark Matter: • Important background for O(10-ton)

direct searches• detectors sensitive for accelerator

produced DM.


COHERENT future, in n-alley

08/19

• 16kg Ge array, coming soon

• multi-ton NaI, shielding/veto configuration to be finalized

• ton-scale LAr (CENNS-750), funding pending

• D2O for flux normalization

• also NIN cubes

• neutron background measurements


COHERENT future, large LAr detector

08/19

CENNS-750: • Based on our experience with CENNS-10 detector, running

since 2017.• Single-phase LAr (scintillation-only) calorimeter, 750/610kg

total/fiducial• Purpose-designed cryostat w/LN2 precool, and dual

cryocooler for liquification/gas purification.• Light collection: TPB coated reflectors combined with

3”PMTs/SiPMs• Eventual use of underground (low 39Ar) argon.

• 3000 CEvNS, 440 inelastic CC/NC events/yr !CENNS-750

SiPM assembly3” PMT assembly


COHERENT future, large LAr detector

08/19

CENNS-750:It fits into n-alley (barely)

event rates in 610kg fiducial LAr detector:

~3000 CEvNS events/year


CENNS-750 LAr detector

08/19

simulated CEvNS + background rates

unsubtracted data,atmospheric Ar

unsubtracted data,underground argon

subtracted data

~440 inelastic CC/NC events/yr

estimated inelastic CC/NC CEvNS rates


Search for accelerator-produced, low-mass, dark matter

Via:

21

COHERENT future

D. Pershey, pub in draft

arXiv:1505.07805



Via:

22

COHERENT future


10-ton LAr or ~2-ton cryogenic NaI detector downstream from high power neutron target, eg SNS


COHERENT future

10 ton LAr

multi-ton NaIWill enable other CEvNS physics as well!


Summary:• First measurement of CEvNS in COHERENT CsI[Na] at the SNS!• More results, demonstrating N2 dependence, with LAr (and others) coming soon.• High potential physics output of CEvNS is driving further work on improved/larger

detectors• Thanks to COHERENT collaboration!

postdoc position open!inspirehep.net/record/1725448


Backups


COHERENT future, beyond n-alley

Sterile oscillation search with large CEvNS detector at SNS

cevnswith liquid argon scintillation detector(s)

Documents